Electrostatic bypass member



July 7, 1936.

W. FOERSTE ELECTROSTATIC BYPASS MEMBER Filed March 24, 1954 'Ol'OOOOOOO'OOO'OIOO'O INVENTOR W/LL/AM FOERSTE I I I ATTORNEY Patented July 7, 1936UNITED STATES PATENT OFFICE ELECTROSTATIC BYPASS MEIWBER of New YorkApplication March 24, 1934, Serial No. 717,284

4 Claims.

The invention relates to by-pass members suitable for use in restoringto operation, for example,

the remainder of a bank of neon lamps after one or more lamps thereofhave become inoperative, and also to protect transformer apparatusagainst possible excessive voltages under open circuit conditions of itssecondary.

Various eXpedients have been proposed to meet these contingencies; andit is an object of the present invention to provide a simple, effectiveand relatively inexpensive member operating electrostatically, whenthese abnormal conditions obtain, to shunt or by-pass the defectiveelement or portion subjected to excessive potential.

A further object of the invention resides in the provision of a memberof this nature which will admit of being readily restored, eithermanually or automatically, to its normal-.state upon correction of theabnormal condition.

In carrying out the invention, an evacuated vessel is provided with twoelectrodes whose one pair of ends extend outwardly through the vesselfor external connection while the other pair of ends are yieldable andjuxtaposed, but separated sufficiently so as to be attracted only whenabnormal voltage conditions prevail. This attraction, under excessiveimpressed voltages, will cause the yieldable free ends to move intocontact with incandescence of the said wire ends and their weldingtogether upon actual contact. The weld may be regulated to be only overan extremely small area so as to lend itself readily to separation andthe restoration of the by-pass member to its original state, when theabnormal conditions are removed, as by a slight mechanical tap or blowdirectly upon the vessel or, as a matter of fact, upon any mechanicallyconnected part. Furthermore, the said juxtaposed ends are caused tooverlap slightly and may be helically coiled so as to obviate undesiredbreaking of the weld through flexing thereof upon cooling.

The nature of the invention, however, will best be understood whendescribed in connection with the accompanying drawing, in which:

Fig. 1 is a more or less diagrammatic view illustrating the applicationof the novel by-pass member to a neon lamp lighting system; and Fig. 2is a similar view illustrating a modification.

Fig. 3 is an enlarged view, in elevation, illustrating the novel by-passmember.

Referring to the drawing, more particularly Fig. 3 thereof, I0designates an evacuated vessel, as a glass tube, the evacuation havingbeen carried to such an extent as to provide for extremely high vacuumor a hard tube. Extending through the opposite ends of this tube arerigid metal electrode members H and I2 affording the terminals l3 and M,respectively, exteriorly of the tube for impressing voltage upon saidelectrodes.

The respective inner extremities l5 and I6 of these electrodes areyieldable or more or less flexible and may consist of separate wires andof a material such as tungsten, Nichrome, carbon, etc. This yieldingproperty may be attained by providing them in the nature of thehelically coiled portion shown, and the convolutions being of adiameter, for example, of .003 to .005".

Moreover, these ends l5 and B6 are juxtaposed, overlapping each other toa slight extent, say .075, and are also separated normally a very slightamount, the separation being of the order of magnitude of .050. Theseparticular dimensions are, of course, subject to variation in accordancewith conditions of operation. 2

Furthermore, it has been found desirable to so proportion theseelectrode extremities, as to weight or volume or both, that theirnatural periods of vibration shall differ appreciably from the frequencyof any applied voltage or other disturbing influences and in order thatthey may not be tuned mechanically to a state to be set into vibrationor actuation other than through the electrostatic attractions developedbetween the said cooperating electrodes.

Such attraction will be determined only by the abnormal conditions whichit is the purpose of the by-pass member to protect against; and it is afunction of the magnitude of the separation, degree of flexibility ofthe ends and the extent of their overlap.

The practical application of this novel by-pass member is indicated inFig. 1 of the drawing wherein the secondary 20, of the usual magneticleakage type transformer mounted in the casing 2|, is connected to theterminals 22 and 23 of a neon lamp bank comprising the individualletters 24, 25, 26 and 21. Provision is made to ground to the lamp bankcasing (not shown) and through a by-pass member 30 one or the other halfof the halves of the lamp bank should failure occur therein. Thus, if aleak or crack should develop in the section comprising the lamps 24 and25, the voltage on the remaining section would become overbalanced andthe grounded bypass member 30 caused to function together with a similarby-pass member 3| connected to the midpoint 32 of the secondary of thetransformer and grounded, for example, to the casing 2| thereof. Thiswill leave the remaining sections,

comprising the lamps 26 and 2'6, illuminated and operative.

At the same time, the end portion of the secondary 28 of the transformercorresponding to the darkened lamps will be operating on open circuitand will set up an excessive voltage across a further by-pass member 33which is connected between the terminal at this end of the secondary andthe grounding casing 2| of the transformer, so that this open circuitbecomes closed and excessive voltage upon the secondary coil portion isavoided. Similarly, a by-pass mem-- ber 34 connected between theopposite terminal of the secondary 2S and the casing 25 of thetransformer will protect this particular end portion of the secondary inthe event that the opposite section of the lamp bank, and comprising theletters 24 and 25, should remain operative and the letters 26 and 2?become inoperative.

In Fig. 2, the secondary 40 of the transformer, in casing GE, is shownconnected as in the previous embodiment to the opposite terminals 42 andd3 of a lamp bank of individual letters 44, 65, it and it; but in thisinstance each individual letter is protected by a by-pass element 48, 9,50 and 5:, respectively, and no ground connection provided for secondary36. In this embodiment, the novel by-pass element wiil shortcircuit,through the momentary high vol developed, an individual letter in theevent of failure thereof, by-passing the said letter and permitting theremaining ones to remain illuminated. By this expedient, the voltagedeveloped in the transformer secondary at is then reduced rather thanincreased. This is highly desirable as well as the fact that the by-passmembers, having once been tripped, will remain so until restored andwill therefore not be effected by any switching on or off of the sign asa whole, as in the case of flashing signs. The transformer and wiringvoltages, therefore, will always be kept within their safe rating.

This property of the inner terminals of the lay-pass member to weldtogether under predetermined electrostatic conditions and maintainthereby a by-pass condition renders the protection permanent, and untilagain restored when the conditions have been corrected; and byconstructing the said inner ends of the electrodes to be of a flexiblenature, the permanency of the weld is insured as the cooling of thejuncture and electrodes after welding will not cause flexing of thelatter to an extent suificient to break the weld.

However, should it be desirable to provide for an automatic restoringaction, the cooperating by-pass member for connection across a highvoltage circuit, comprising a pair of normally separated relativelymovable electrodes approaching each other solely in response to theelectrostatic influence afforded by the circuit and of mass adapted uponcontacting of the electrodes to weld the same together, and a vesselenveloping the electrodes and evacuated to a degree preventing arcingand ionization in the space between electrodes, the latter affordingterminals externally of the vessel.

3. An electrostatic, removable circuit-closing by-pass member forconnection across a high voltage circuit, comprising a pair of normallyseparated relatively movable electrodes approaching each other solely inresponse to the electro static influence afforded by the circuit and ofmass adapted upon contacting of the electrodes to weld the sametogether, the said electrodes at their free ends being constructed toaccommodate the effects of temperature changes so as to maintain theweld, and a vessel enveloping the electrodes and evacuated to a degreepreventing arcing and ionization in the space between electrodes, thelatter affording terminals externally of the vessel.

4. An electrostatic, removable circuit-closing by-pass member forconnection across a high voltage circuit, comprising a pair of normallyseparated relatively movable electrodes approach ing each other solelyin response to the electrostatic influence afforded by the circuit andof mass adapted upon contacting of the electrodes to weld the sametogether, the said electrodes having helically coiled free ends tomaintain the weld. and a vessel enveloping the electrodes and evacuatedto a degree preventing arcing and ionization in the space betweenelectrodes, the latter affording terminals externally of the vessel.

WILLIAM FOERSTE.

